犬弓首蛔虫ITS1基因的克隆及序列分析

通过对国内5个犬弓首蛔虫株(T.canis)即GD株、CQ株、YN株、HN株和GZ株的rDNA的内转录间隔区Ⅰ(ITS1)序列进行PCR扩增、克隆、测序和序列分析,旨在确定ITS1是否可作为T.canis分子分类的遗传标记。结果显示:GD株、CQ株、YN株、HN株和GZ株的ITS1序列基本一致,仅GD株有2个碱基的差异,HN株和GY株分别有1个碱基的差异;与GenBank中登录的T.canis(序列号为AB110024、AB110026)的ITS1序列同源性高达98.9%～99.4%。结果表明ITS1可作为分子标记用于T.canis与其它蛔虫的种间鉴定,但不适合用于T.canis种内遗传变异的研究,为进一步的分子遗传学和分子诊断学研究奠定基础。     

Missense polymorphisms in the MC1R gene of the dog,red fox,arctic fox and Chinese raccoon dog

Coat colour variation is determined by many genes, one of which is the melanocortin receptor type 1 (MC1R) gene. In this study, we examined the whole coding sequence of this gene in four species belonging to the Canidae family (dog, red fox, arctic fox and Chinese raccoon dog). Although the comparative analysis of the obtained nucleotide sequences revealed a high conservation, which varied between 97.9 and 99.1%, we altogether identified 22 SNPs (10 in dogs, six in farmed red foxes, two in wild red foxes, three in arctic foxes and one in Chinese raccoon dog). Among them, seven appeared to be novel: one silent in the dog, three missense and one silent in the red fox, one in the 3′‐flanking region in the arctic fox and one silent in the Chinese raccoon dog. In dogs and red foxes, the SNPs segregated as 10 and four haplotypes, respectively. Taking into consideration the published reports and results of this study, the highest number of missense polymorphisms was until now found in the dog (9) and red fox (7).     

Risk of Toxocara canis eggs in stray and domestic dog hair in Egypt

The aim of the study was to assess whether the hair of stray and domestic dogs in Egypt was contaminated with the eggs of the zoonotic parasite Toxocara canis, and also to identify risk factors for T. canis for contamination. Paired samples of hair and feces were collected from 53 stray and 47 domestic dogs, and hair samples were obtained from a further 11 stray and 9 domestic dogs. All samples were examined to identify T. canis eggs and, if eggs were found, their maturation stage. Eggs were identified in 26.6% of stray and 10.7% of domestic dog's hair samples. A significantly increased risk of embryonated T. canis eggs in hair samples was found in stray dogs (p=0.04), stray dogs had 3.18 (95% CI: 1.04-9.74) times the odds of having T. canis eggs present compared with domestic dogs. There was also a significant difference (p=0.02) between the mean quantity of eggs per gram in stray (77.6±6.54) and domestic (48.7±6.65) dog's hair. Fecal examination found a T. canis egg prevalence of 35.8% and 21.3% in stray and domestic dogs, respectively. As no domestic dogs which were positive from hair samples had negative fecal samples, this indicates that the presence of T. canis eggs in hair is probably due to self contamination. Two stray dogs had positive hair samples but negative fecal samples indicating that contamination may also be environmental. As both non-embryonated and embryonated T. canis eggs were found in the hair of domestic dogs, direct contact with dogs may be a potential risk factor for transmission of T. canis eggs to humans.     

Epidemiology of Toxocara canis in the dog population from two areas of different socioeconomic status,Greater Buenos Aires,Argentina

Toxocara canis infection in dogs is a public health problem in most countries, although it has been poorly documented in many of them. The main objective of the present work was to investigate the epidemiology of infection in the canine populations from two areas of Buenos Aires of different socioeconomic status and urban conditions: a middle-income neighbourhood (MIN) and a low-income neighbourhood (LIN). This study evaluated the prevalence of infection in dogs by parasitological and serological techniques in both areas, and described the relationship between the infection and different epidemiological variables for each neighbourhood. A cross-sectional study was carried out after a house-to-house census was completed. During August 1999, a sample of households was selected at random (nMIN=53 and nPA=52). In each house, one dog was randomly chosen for the collection of fresh faeces and blood. The dog owners were interviewed utilising a questionnaire about dogs on sex, recent anthelmintic treatment, degree of confinement, control by the dog's owner (whether the dog goes out of the house accompanied or not, leashed or unleashed), defecation site, defecation substratum and number of dogs in the house. The diagnostic techniques were concentration-sedimentation formalin/ether method and ELISA test. The parasitological prevalences in dogs were 9% (5/53) in MIN and 19% (10/52) in LIN, and serological prevalences were 22% (2/9) in MIN and 40% (15/37) in LIN. In MIN, the patent infection of males was significantly higher than that of females. In LIN, puppies less than 1 year old were the most prevalent age class. Our serological results showed that the positivity of adult dogs was more frequent in LIN than in MIN. The density of puppies with patent infection was seven times higher in LIN than in MIN, when combining coprological analysis and the estimated age structure obtained by the census.     

兰狐和银黑狐免疫球蛋白的提纯与鉴定

采用硫酸铵盐析和Agarose-Protein G亲和层析相结合的方法，从兰狐和银黑狐血清中提取和纯化了免疫球蛋白（IgG），应用SDS-PAGE分析表明：提纯的免疫球蛋白纯度高，重链和轻链的分子量分别为45ku和21ku左右；以犬瘟热病毒（CDV）为包被抗原的间接ELISA试验结果表明：提纯的蛋白免疫小鼠分别制备的抗兰狐和银黑狐免疫球蛋白抗体作为二抗检测CDV阳性血清具有良好的生物活性。本研究制备的高纯度的兰狐和银黑狐免疫球蛋白，对今后狐源CDV等疫病血清流行病学的调查、诊断试剂盒的开发及疫苗免疫效果的评价奠定了基础。     

Echinococcus multilocularis and Toxocara canis in urban red foxes (Vulpes vulpes) in Brussels, Belgium

During the last decades, European red foxes (Vulpes vulpes) have been implicated in the transmission of several viral or parasitic pathogenic agents to domestic animals and humans. In urban areas, risks of zoonoses transmission are likely to increase as a result of a higher rate of intra- and inter-species contacts. Foxes occur on 35% of the Brussels-Capital Region area and local densities reach up to 4 family groups per square kilometre. According to the directive 2003/99/ECC, a first survey for the presence in foxes of Echinococcus multilocularis and Toxocara canis was conducted in Brussels from 2001 to 2004. None of 160 foxes were found to be infected with E. multilocularis and 24 of 134 foxes were found to be infected with T. canis. Considering numbers of examined foxes, the sensitivity and the specificity of tests used for diagnosis, the 95% credibility intervals for the true prevalence of E. multilocularis and T. canis were estimated in a Bayesian framework to be 0 to 1.87% (median value of 0%) and 12.7 to 26% (median value of 18.7%), respectively. For T. canis, a significantly higher risk to be a carrier occurs in cubs and a significantly lower risk in adults.     

A comparison of the protein constituents of the major body compartments of the dog roundworm, Toxocara canis

An analysis of the protein profiles of intact worms and isolated tissues of adult male and female Toxocara canis worms was conducted. Soluble proteins recovered from homogenized whole specimens and dissected tissues (body wall, reproductive tract, esophagus and intestine) of T. canis adults from several different canine hosts were separated by size using gradient sodium dodecyl sulfate electrophoresis (SDS-PAGE) and visualized with silver staining. SDS-PAGE profiles of worms from different hosts were found to be virtually identical irrespective of sex or tissue type. Recovered proteins ranged in size from 3.4 to 325 kDa. As expected, variations existed between the protein profiles of different body tissues, with only slight variations between the sexes. The largest number of recovered proteins was present in the female reproductive tract extracts.     

Hosts of two canid genera, the red fox and the dog, as alternate vectors in the transmission of Sarcocystis tenella from sheep

Microscopic sarcocysts recovered from naturally infected sheep were infective to both the domestic dog (Canis familiaris) and the red fox (Vulpes vulpes). The parasite was passaged through experimental specific-parasite-free (SPF) sheep three times: infection was transmitted twice with sporocysts from foxes and subsequently with sporocysts from dogs. The sarcocysts from sheep muscle were infective to both dogs and foxes on each occasion. A cat was not infected. The prepatent period in individual canids ranged from 7 to 15 days. Sporocyst excretion was still detectable 60 days post infection. This study establishes that canids of two genera may act as vectors for a single isolate of the same Sarcocystis species from sheep.     

In vitro susceptibility to antimycotics of Microsporum canis isolates from cats.

One hundred thirty-four isolates of Microsporum canis, obtained from cats, were tested for in vitro susceptibility to various antifungal agents. The fungi were classified as susceptible, resistant, and intermediate by measuring the size of the zone of inhibited growth on yeast nitrogen base agar medium. Clotrimazole had the highest activity (99.2%), followed by tioconazole (89.6%), griseofulvin (88.8%), econazole (73.1%), ketoconazole (50.7%), miconazole (15.7%), and isoconazole (12.7%). We found 14.9% of the isolates to be susceptible to all the assayed drugs, whereas the highest resistance frequency (41.8%) was against 2 antimycotics. A simultaneous resistance to all the tested antimycotics was not found. The differences among the antifungal drugs activity were examined, and administration of drugs for which a simultaneous resistance was minimal is suggested.     

Differentiation of Toxocara canis and T. cati eggs by light and scanning electron microscopy

In this study, we investigated the morphological identification of Toxocara canis and T. cati eggs on the basis of light and scanning electron microscopic (SEM) observations. T. canis and T. cati eggs used in this study were recovered from the uteri of respective gravid female worms. Measurement of egg size was not helpful in the differentiation of these species, because approximately 90% of eggs measured were of similar size. Using SEM, we were able to differentiate T. canis eggs from T. cati eggs based on their respective characteristic surface structures. Both species have subspherical eggs with markedly pitted surfaces like those of a golf ball, but the surface pitting in T. canis is more coarse than that in T. cati. In this study, however, these differences were not absolute, as 16% of T. canis and 29% of T. cati eggs showed surface pitting that was uncharacteristic of their species. Of the 16% of T. canis eggs that could not be differentiated by surface structure, 3% had pitting resembling T. cati, and the remaining 13% showed intermediate type surface pitting. Similarly, 5% of T. cati eggs resembled T. canis, and 25% of these were of intermediate type. Light microscopic observation yielded results similar to those of SEM, indicating that light microscopy is also a useful tool for the identification of Toxocara eggs.     

Investigations into the prevention of prenatal and lactogenic Toxocara canis infections in puppies by application of moxidectin to the pregnant dog

Aim of the investigation was to examine whether two administrations of moxidectin to pregnant dogs could prevent pre-natal and lactogenic infections of puppies with reactivated Toxocara canis larvae. Four pregnant beagles, infected experimentally with 20 000 embryonated eggs of T. canis, were treated subcutaneously with 1 mg moxidectin per kg body weight on days 40 and 55 of pregnancy (5-13 days before parturition). One further dam and its puppies served as untreated control. Two applications of moxidectin completely prevented pre-natal and lactogenic infections in the puppies. Neither intestinal stages nor somatic larvae were found in the dams or their corresponding puppies. All puppies and dams of the treatment group remained coproscopically negative until 42 days after parturition. The administration of moxidectin did not show any side effects in the dams. None of the puppies of the treated dams showed any pathological abnormalities. In the untreated dam one adult and 26 somatic larvae of T. canis were detected at necropsy. All puppies of the untreated dam showed a patent T. canis infection from day 28 post-natum (p.n.); 296 pre-adult and adult stages of T. canis were spontaneously eliminated and 51 intestinal stages and five somatic larvae of T. canis were recovered at necropsy. In contrast to the puppies of the treated dams all negative control puppies showed blood eosinophilia after parturition and elevated liver enzyme levels.     

从死胎流产的母貉体内检出1株犬链球菌

为确定引起母貉死胎、流产的病原,采集流产仔貉脏器,流产母貉阴道分泌物进行病原菌的分离培养、纯培养、形态观察、致病性试验确定分离菌株为致病菌。并采用ATB全自动生化鉴定系统进行生化鉴定,鉴定该菌为犬链球菌(S.canis)。该菌的16S rRNA基因系统发育树分析结果表明,分离菌与S.canis同源性达94.5%~99.3%。溶血活性结果表明,该病原菌在血平板上呈β型溶血。药敏试验显示,该菌对阿莫西林、氧氟沙星、磷霉素、头孢他啶等药物敏感。     

A serosurvey of Hepatozoon canis and Ehrlichia canis antibodies in wild red foxes (Vulpes vulpes) from Israel

A seroepidemiological survey was conducted to investigate the prevalence of antibodies reactive with Ehrlichia canis and Hepatozoon canis antigens in free-ranging red foxes (Vulpes vulpes) in Israel. Of 84 fox sera assayed, 36% were seropositive for E. canis by the indirect fluorescent antibody (IFA) test and 24% were positive for H. canis using an enzyme-linked immunosrbent assay (ELISA). Canine ehrlichiosis and hepatozoonosis appear to be endemic in the wild red fox populations in Israel, and foxes may serve as a reservoir for infection of domestic dogs and other wild canine species.     

Prevalence of Ehrlichia canis, Anaplasma platys, Babesia canis vogeli, Hepatozoon canis, Bartonella vinsonii berkhoffii, and Rickettsia spp. in dogs from Grenada

To identify the tick-borne pathogens in dogs from Grenada, we conducted a serologic survey for Ehrlichia canis in 2004 (104 dogs) and a comprehensive serologic and molecular survey for a variety of tick-borne pathogens in 2006 (73 dogs). In 2004 and 2006, 44 and 32 dogs (42.3% and 43.8%) were seropositive for E. canis, respectively. In 2006, several tick-borne pathogens were identified by serology and PCR. DNA of E. canis, Anaplasma platys, Babesia canis vogeli, Hepatozoon canis, and Bartonella sp. were identified in 18 (24.7%), 14 (19.2%), 5 (7%), 5 (7%), and 1 (1.4%) dogs, respectively. Six (8.2%) dogs were seropositive for Bartonella vinsonii subsp. berkhoffii. All dogs were seronegative and PCR-negative for Rickettsia spp. Coinfection with two or three pathogens was observed in eight dogs. Partial 16S rRNA E. canis and A. platys sequences were identical to sequences in GenBank. Partial 18S rRNA gene sequences from the Grenadian H. canis were identical to each other and had one possible mismatch (ambiguous base) from H. canis detected from Spain and Brazil. Grenadian B. c. vogeli sequences were identical to B. c. vogeli from Brazil and Japan. All of the detected pathogens are transmitted, or suspected to be transmitted, by Rhipicephalus sanguineus. Results of this study indicate that dogs from Grenada are infected with multiple tick-borne pathogens; therefore, tick-borne diseases should be included as differentials for dogs exhibiting thrombocytopenia, leukopenia, fever, or lethargy. One pathogen, E. canis, is also of potential public health significance.     

The helminth fauna of the red fox (Vulpes vulpes LINNE, 1758) in Nordhessen and Ostwestfalen. 2. Nematodes]

Between November 1989 and June 1990 a total number of 397 foxes were examined for the presence of nematodes in the stomach and the small intestine and 403 foxes for the presence of Trichinella spiralis larvae. The animals came from the districts of Kassel, Arnsberg and Detmold. In 32.7% of the foxes infections with Toxocara canis were found, in 11.1% Toxascaris leonina, in 3.8% Ancylostoma caninum, in 3.5% Uncinaria stenocephala and in 2.3% Capillaria species. In most cases the number of nematodes per fox was low. Only Toxascaris leonina was frequently found with more than 20 specimen per animal. Trichinella spiralis larvae were not found in any of the foxes.